lungs Flashcards
how many lobes are in the right lung?
3
upper, middle, lower
how many lobes are in the left lung?
2
upper, lower
which lung has the cardiac and aortic notch?
left
how does the bronchial tree branch?
one branch fro each lobe
what are the filter characteristics of the respiratory tract?
nose hair
- large particles of dirt and dust etc from air get trapped
mucous
- small particles from air (sticky)
which air entrance is more filtered?
nose
mouth is less (dirtier air)
when air enters the body what 3 things happen to it?
filtered
humidified to body temperature
cleaned
which is anterior the oesophagus or trachea?
trachea is anterior to the oesophagus
upper respiratory tract
nose
moth
pharynx
larynx
lower respiratory tract
trachea
bronchi
bronchioles
alveoli
what are the divines of the bronchus?
main (primary)
lobar (secondary)
segamental (tertiary)
what is the cardia?
break between the right and left main bronchi
what bronchus is more vertical?
right bronchus is more vertical than left
- left is more lateral/flat
more likely to have thing go into right main branches due to gravity
what are the conducting zone components?
conducting brinchioles (4-20 branch points)
terminal branches
what are the respiratory zone components?
respiratory bronchioles
alveolar ducts
alveolar sacs with alveolus
what happens when inhaling?
increased thoracic volume
so decreased pressure inside compared to outside
- air moves in
increase in pulmonary pressure to equal atmospheric pressure
what happens when exhaling?
decreased thoracic volume
increased pressure
air moves out
decreased in pulmonary pressure to equal atmospheric
what happens to muscles and alveoli in inhalation?
muscles contract
- needs energy (active process)
alveoli stretched open
- elastin protein around them
what happens to muscles and alveoli in exhalation?
muscles relax
- passive process
alveoli recoil
- drives exhalation
why do we repsire?
need O2
- respiration, metabolise food for ATP
release CO2
air pathway
oral and nasal cavity
connect at pharynx
larynx
___
trachea
2 main bronchi —> lobar bronchi —> segmental bronchi
bronchioles
alveoli air sacs
does the trachea have cartilage?
yes, the trachea has cartilage rings
do bronchi have cartilage?
no, bronchi does not have cartilage
- cartilage stops at trachea
alveoli properties
very thin walls - one cell thick
circulatory system passes right by alveoli
- deoxygenated blood vessels from heart (pulmonary arteries)
- molecules O2 absorbed into blood via alveoli capillaries
- oxygenated blood returns to heart (pulmonary veins)
- CO2 from blood diffuses into lungs and is exhales
macrophages
part of the innate immune system
agranulocytes
engulf pathogens in alveoli that were not caught by mucous earlier in respiratory tract - PHAGOCYTOSE
- important as difficult to treat infection when entered blood circulation
what is the fraction inspired O2?
FIO2 = 21%
nitrogen 78%
argon 1% (inert, doesn’t react in body)
others <1%
what is PO2 at entrance to body (mouth)?
= fraction inspired O2 x atmospheric pressure
= FIO2 x Patm
= 0.21 x 760mmHg
= 160mmHG
why does PO2 decrease in lungs compared to entrance to body?
decrease due to water vapour
what is PO2 in lungs?
= fraction inspired O2 x (Patm - PH20)
= 0.21 x (760mmHG - 47 mmHg)
= 0.21 x 713
= 150mmHg
what is the respirator quotient?
RQ = 0.8
the ratio of the volume of carbon dioxide evolved to that of oxygen consumed by an organism, tissue, or cell in a given time.
is CO2 or O2 more soluble in pulmonary blood?
CO2 is 20 times more soluble than O2 in pulmonary blood
what is Henry’s Law?
P / Kh = concentration at surface layer
increased solubility causes increased pressure
Kh is the likelihood of leaving liquid phase - constant
higher partial pressure means….
more likely gas will enter liquid phase - soluble
pathway for O2 to enter blood from alvoli
O2 enters liquid phase ro cross layer of fluid in alveolus
through epithelial
through basement membrane and connective tissue
through basement membrane (capillary side)
through endothelial cells and plasma
bind to haemoglobin in RBC
- have 4 O2 binding sites
what are baroreceptors?
nerves that detect pressure and stretch in vessels
send information to brain - regulates BP
where are baroreceptors found?
in carotid since and aortic arch
what are peripheral chemoreceptors?
detect pO2, pCO2 and pH level changes
made of supportive cells and glomus cells
have a lot of blood flwo
where are peripheral chemoreceptors?
aortic body - on aortic arch
carotid bodies - near bifurcation of carotid arteries
what nerve is connected to the aortic body?
vagus nerve CNX
what nerve is connect to the carotid bodies?
glossopharyngeal nerve CNIX
what is the effect of low pO2 on peripheral chemoreceptors?
glomus cells detect and depolarises
- specialised K+ channels are inhibited so no out flow
- Ca2+ flows in
release neurotransmitter dopamine from vesicles
sends AP down neuron
- level of O2 corresponds to amount neurotransmitter reeled (lower pO2 = more neurotransmitter = more APs)
what is the effect of high pCO2 on peripheral chemoreceptors?
CO2 made by gloms cells
- diffuses out into blood
high pCO2 means difficult for CO2 to diffuse from gloms cells into blood
- build up of CO2 in glomus cells
glomus cells release neurotransmitter –> AP
- level of pCO2 correspisne to number of AP released
PCO2 has greater effect on central chemoreceptors
where are central chemoreceptors located?
in CNS
posterior to DRG in brainstem (pons and medulla oblongata)
what do respiratory centres receive information on?
respiratory centres are a collection of neurons which receive information on CO2
when high pCO2 there is a decreased diffusion gradient between blood and interstitial fluid
build up of H+ around central chemoreceptors
- cause more APs to be fired
- increased inspiration
CO2 + H2O H2CO3 HCO3- + H+
what do central chemoreceptors respond to?
increased pCO2
increased H+ (lower pH)
but not decreased pO2
-only peripheral chemoreceptors respond to low pO2 (less than 60mmHg)
what control voluntary breathing?
cerebrum
why do we have voluntary controlled breathing?
playing wide instruments
holding breath
yelling
singing
what do mechanoreceptors do?
send information on pressure, connected to nerve
e.g. baroreceptors; others in nose, lungs, GIT
what is the hypothalamus role in respiration?
region of brain which sends information to respiratory centre to effect our breathing
response to emotions (anxiety, fear and pain) also temperature (e.g. jump into cold water)
what is emphysema
gradual destruction of alveoli
healthy lungs have large SA for gas exchange
emphysema causes ruptured air sacs
- large spaces instead of many smaller places
- decreases SA for gas exchange
what is bronchitis
inflamed main bronchus
what is pneumonia
inflamed alveoli
what is laryngitis
inflamed larynx
what is the airs passageway from environment to alveoli?
nasal cavity
pharynx
epiglottis
larynx
tranchea
carina
main bronchus
lobar bronchus
segmental brings (tertiary)
conducting bronchioles
respiratory bronchioles
alveolar ducts
alveoli
what is surfactant
fluid made by type II alveolar cells
which decreases surface tension
pleural cavity
contains serous fluid which facilitates lining movement within the thoracic cavity
cilia role in respiratory tract
move contaminated mucus away from lungs and towards mouth so it can be expelled or swallowed
pulmonary artery
brings deoxygenated blood from right ventricle to the lungs
2 in total
pulmonary veins
bring deoxygenated blood from the lungs to the left atrium
4 in total
what can cause adult onset asthma
skiing
cold, dry air damages lower respiratory tract
chloride shift
70% of CO2 in pulmonary blood is in bircabonate form HCO3-
channels shunts bicarbonate into haemoglobin
- negative charge entered
counteracted as Cl- leaves to prevent membrane from becomin too negative
carbonic anhydrase
speeds up conversion of H2CO3 to CO2 and H2O (after HCO3- binds with H+)
only in blood cells not in circulating plasma
- plasma has slower CO2 release due to no enzyme action
HCO3-
bicarbonate
weak base
H2CO3
carbonic acid
weak acid
R state haemoglobin
oxyhemoglobin
increase O2 affinity - loading
low CO2 and H+ affinity - unloading
T state haemoglobin
deoxyheamglobin
decreased O2 affinity
high CO2 and H+ affinity
Haldane effect
Oxygenation of blood in the lungs displaces carbon dioxide from haemoglobin which increases the removal of carbon dioxide (O2 loading)
Conversely, oxygenated blood has a reduced affinity for carbon dioxide (CO2 and H+ unloading)
OXYHAEMOGLOBIN CURVE
